TD reently announced that they would be changing the way they put a charge on your title when you obtained a mortgage from them. They will now be making the mortgage a collateral mortgage. This will allow you to get a line of credit or increase your mortgage without having to have the paperwork done over again.
So, what's the downside? It will be much more difficult to get out of a TD mortgage if another better mortgage comes along. See the attached link for more details.